Need to find a necchi supernova bu check spring

The manual is $4.99.

https://manualsoncd.com/product/necchi-bu-sewing-machine-instruction-manual/

This says Free

https://millardsewing.com/product/necchi-model-bu-mira-instruction-manual-free-download/

How To Date A Necchi Sewing Machine - SewingFeed

sewingfeed.com https://sewingfeed.com > how-to-date-a-necchi-sewing...
Mar 6, 2023 - The easiest way to date a Necchi sewing machine is by identifying the model you have and then researching what year it was made in Necchi brand ...

‎Where Is Serial Number On... · ‎Where is the model number on...

How Old Is My Necchi Sewing Machine? (Vintage ...

SewingIsCool.com https://sewingiscool.com > how-old-is-my-necchi-sewi...
Finding the age of the Necchi sewing machine that you personally own doesn't take too much effort. You need the serial number and possibly the model number.

Necchi Sewing Machine Serial Numbers ' Peatix

Peatix https://necchi-sewing-machine-serial-numbers269.peatix.com The BU is a flat bed machine with an oscillating hook and manual zig zag (which I believe means you select zig zag by shifting the stitch width lever rather ...

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Hopefully, this procedure will correct that problem.
It is very important to check whether the position of the tension mechanism is correct.
-Set the presser bar lever in its intermediate (embroidery) position.
-Check that the disc opening rod "B" in the below figure is as close as possible to the disc opening lever "N" without actually touching.

-Ensure that the thread take-up spring can move freely without rubbing against the machine arm. Distance "a" in the below figure should be about 1/16" (1.5mm)

If an adjustment is needed, loosen screw 048050 GEB and move the entire tension mechanism along its axis (do not rotate it) then tighten screw 048050 GEB firmly.
pics with the above here.....
http://sewing-machines.blogspot.com/2014/02/necchi-supernova-tension-release.html
hope this helps.
Happy sewing!

Most sewing machines can use a double needle, the one with the single mounting shank and it turns into two needles.
MAKE sure you have Zig Zag needle plate installed to accomodate the double needle.
Turn hand wheel slowly to test then use thread and fabric and turn flywheel by hand to test sew.

Necchi BF is a straight stitch machine
Necchi BU is zig zag machine
Necchi BU Supernova had cams for additional stitches

check this link for parts and see if it's what you need

http://www.sewingpartsonline.com/necchi-supernova-ultra-mark-2-sewing-machine-parts.aspx

You may have to find a dealer who can help you with a replacement.

http://www.allynint.com/

found another website that showed the thread path

sounds to me like a tension issue, also are you using rayon or polyester thread, this is just a recommendation for those types of threads,,,,,,but please check your tension, is it only doing it during automatic

http://www.sewusa.com/Threading_Diagrams/Threading_Pages/Necchi_Sewing_Machine_Threading/Necchi_BU_threading_Diagram.htm

this site has a picture

All I did was google Necchi Supernova and the second link that came up was a threading diagram...